FIGURE 4.

Impacts of the intervention tasks on reducing individuals’ impulsivity (experiment 2). In experiment 2, three types of intervention task (working memory, Control_WM, and rest) were tested. To examine whether each intervention had an impact on individuals’ impulsivity, we calculated changes in individuals’ delay discount rates (k) by comparing their behavioral patterns during the ITC task conducted before and after the intervention task. The individuals showed significantly reduced impulsivity after participating in the Control_WM task [paired t-test, t(20) = 2.07, P = 0.049, Cohen’s d = 0.41, bootstrapping P = 0.051]. On the contrary, the individuals who participated in the other intervention tasks including the working memory task did not show the same pattern (all bootstrapping ps > 0.05). The mean discount rate change in individuals who participated in the Control_WM task was not larger compared with that in individuals with any intervention task (all bootstrapping ps > 0.05). Each dot represents an individual participant, and error bars indicate s.e.m.; *P < 0.05.